Re: INSERT...ON DUPLICATE KEY LOCK FOR UPDATE

On Tue, Dec 31, 2013 at 12:52 AM, Heikki Linnakangas
<hlinnakangas@vmware.com> wrote:
>> Are you suggesting that I lock the tuple only (say, through a special
>> LockPromiseTuple() call), or lock the tuple *and* call
>> XactLockTableWait() afterwards? You and Robert don't seem to be in
>> agreement about which here.
>
> I meant the latter, ie. grab the new kind of lock first, then check if the
> tuple is still there, and then call XactLockTableWait() as usual.

I don't follow this either. Through what exact mechanism does the
waiter know that there was a wait on the
PromiseTupleInsertionLockAcquire() call, and so it should not wait on
XactLockTableWait()? Does whatever mechanism you have in mind not have
race conditions?


-- 
Peter Geoghegan